1. Field of the Invention
The present disclosure relates to a cryptographic processing device. More specifically, the present disclosure relates to a cryptographic processing device which employs a novel data storing method.
2. Description of the Related Art
Japanese Laid-Open Patent Application Publication No. 2008-165439 (Patent Literature 1) discloses a magnetic disc device including a storage medium section including a storage medium, a magnetic disc medium section including a magnetic disc medium, a storage means which stores data transmitted from a host in the storage medium, a first verification means which verifies a password input externally with a password pre-stored in the storage medium or a semiconductor memory configured on the same board as that of the storage medium, and a control means which is provided in the storage medium section and controls access to the magnetic disc medium configured in the magnetic disc medium section according to a result of the verification of the first verification means.
Japanese Laid-Open Patent Application Publication No. 2010-193013 (Patent Literature 2) discloses a ciphertext key protecting method of a semiconductor memory device including a non-volatile memory including a memory cell array and being operative to encrypt file data input, store the encrypted file data in a portion of the non-volatile memory, and store management information including a key used to decrypt the encrypted file data, in another portion of the non-volatile memory, in which method, in a first state in which password reference by using the management information is valid, the input password is verified, and the encrypted file data is permitted to be decrypted by the key based on a result of the verification, while in a second state in which the password reference by using the management information is invalid, the encrypted file data is permitted to be decrypted by the key without an input of the password, the management information indicating that the first state is formed is stored in the memory cell array by using a first threshold voltage and a second threshold voltage which is lower than the first threshold voltage, and the management information indicating that the second state is formed is stored in the memory cell array by using a third threshold voltage and a fourth threshold voltage which is lower than the third threshold voltage.